Fix cas ammo consumption logic (#5824)

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Fix #5578
# Explain why it's good for the game
Bugs bad
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# Changelog
:cl:
fix: ammo consumption logic for cas tgui correctly counts
/:cl:

tgui/packages/tgui/interfaces/MfdPanels/FiremissionPanel.tsx

@@ -373,7 +373,7 @@ const OffsetDetailed = (
     return <>error</>;
   }
   const ammoConsumption = weaponFm.offsets
-    .map((x) => (x === '-' ? props.equipment.burst : 0))
+    .map((x) => (x === '-' ? 0 : props.equipment.burst))
     .reduce(
       (accumulator, currentValue) => (accumulator ?? 0) + (currentValue ?? 0),
       0